If set, specifies the maximum time before which a worker processing a task of this type must report progress by calling
RecordActivityTaskHeartbeat. If the timeout is exceeded, the activity task is automatically timed out. If the worker subsequently
attempts to record a heartbeat or returns a result, it will be ignored. This overrides the default heartbeat timeout specified when
registering the activity type using RegisterActivityType. The valid values are integers greater than or equal to 0. An integer
value can be used to specify the duration in seconds while NONE can be used to specify unlimited duration.